Ultra-High-Pressure and Extreme-Pressure Metrology: A Review of Measurement Technologies and Traceability

Ultra-high-pressure and extreme-pressure metrology plays a critical role in advanced manufacturing, geoscience, high-pressure physics, and frontier materials research. As pressure ranges extend from hundreds of MPa to several GPa and beyond, pressure generation and measurement are increasingly constrained by material strength, structural deformation, the state of pressure-transmitting media, sealing reliability, sensor drift, and incomplete traceability chains, imposing higher requirements on pressure metrology. This review systematically examines measurement technologies and traceability routes for ultra-high-pressure and extreme-pressure ranges. The development of controlled-clearance piston gauges is summarized, with emphasis on uncertainty reduction, range extension, and calibration automation. Drop-weight-based primary standards for dynamic pressure are also reviewed as an established route for the traceable calibration of high-amplitude, millisecond-scale hydraulic pressure pulses. Progress in secondary ultra-high-pressure standards is reviewed, including ultra-high-pressure gauges and piezoresistive, resonant, fiber-optic, and triboelectric sensors, with focus on range extension, high-accuracy measurement, environmental adaptability, and emerging pressure-sensitive mechanisms. Measurement methods for extreme pressure, including ruby fluorescence, Raman spectroscopy, X-ray diffraction, phase-transition points, and equations of state, are compared in terms of applicability and limitations. Current challenges in ultra-high-pressure and extreme-pressure metrology are further discussed, together with the prospects of quantum pressure sensing based on nitrogen-vacancy centers in nanodiamonds, providing a reference for future research and metrological infrastructure development.